Pesticidal copper chromates and method of making and applying same



1955 F. R. WHALEY ETAL PESTICIDAL COPPER CHROMATES AND METHOD 5 85% 862193 3 -u m 25 85 2123 3 o M 23 85 2:2 3 3-0 85 -23 3 36 8.5 212 3 5 8522 3 EL 86 29 3 3- w I Q m U Q Q koimx m zkomm mw I m ow mm mm 1 mm ommm mm ww mm om 2 2 E Q o om A5123 at. 3258 2:02 31-x Ri D R. wHALeyCARLE OM N. S IT RlCHARD H. WELLMAN United States Patent PESTICIDALCOPPER CHROMATES AND METHOD OF MAKING AND APPLYING SAME Fred R. Whaley,Kenmore, Carleton N. Smith, Snyder, and Richard H. Wellman, Hastings onHudson, N. Y., assignors to Union Carbide and Carbon Corporation, acorporation of New York Application October 25, 1951, Serial No. 253,065

7 Claims. (Cl. 167-16) This invention relates to pesticidal materialscontaining copper and chromium and to pesticidal compositions containingsuch materials, and to methods of preparing such materials andcompositions and of combatting pests by means of such materials andcompositions. The present application is a continuation in part of thecopending application Serial No. 633,530, filed December 7, 1945, nowPatent No. 2,573,738, dated November 6, The subject matter of thepresent application represents research conducted and findings made withrespect to compounds of copper and chromium, the discovery being thatover a limited range of proportions of these metals and with compoundshaving a certain X-ray pattern there are better disease control andhigher yields of agricultural products than with the same metals inother proportions and in compounds having other X-ray patterns,particularly with respect to potato blights and yields of potatoes underhigh blight potential.

On the accompanying drawing are reproduced X-ray patterns of thematerials to which the present invention relates and of comparativematerials.

The copper chromates of the present invention have a copper to chromiummolar ratio of XCu(OH)z to ICrOs, X being greater than 3 and rangingupwards to include 6, these chromates being distinguished by stronglines on X-ray patterns (CuKu radiation) at values of 20 equal to 13.6,22.3, and 35.5 and weaker lines at 16, 26.4, and 33, as shown on theaccompanying drawing. As will be seen from the drawing, these lines areentirely absent from a chromate where X is 3 or a copper compound whereCrOs is zero. Where X is 5.5, two of the distinctive lines of cuprichydroxide at 23.9 and 36 appear faintly and show more strongly where Xis 6. The preferred chromates are those where X is from greater than 3up to and including 5, the optimum for X being between 4 and 5. All ofthese chromates are basic and all have colors containing a portion ofyellow, that is the colors range from a yellow brown to an olive green,the chromates where X is from 4 to 5 inclusive being a light greenscarcely noticeable on potato foliage or on the green parts of otherplants. Where X is below 5.5 the X-ray patterns indicate the absence ofunreacted copper hydroxide. The pattern (CuKa radiation) for CH0contains two strong lines at 35.6 and 38.8 of almost equal intensity andthe three principal lines for CrOs are at 26.2, 21.1, and 31.3.

In a comparative field test, plots of Russet and Katahdin potato plantswere given regular sprayings of Bordeaux (8-8-100) mixture, a copperchromate designated A, and a copper chromate designated D. Thecomposition of the Bordeaux spray was 8 pounds of CuSO4- 5H2O and 8pounds of CaO per 100 gallons of water. copper chromate A analyzed 3Cuto lCr (indicating a formula which may be written 3Cu(OH)z-1Cr0s) andhad the X-ray pattern shown on line A of the attached drawing. Theanalysis of copper chromate D indicated the formula 4.5CuO-1Cr0a. shownon line D of the attached drawing. Both chromates were used at the rateof 2 pounds per 100 gallons of water. All sprays contained 2 pounds of50% wettable DDT powder per 100 gallons. The sprayings were at the ratesof about 125 gallons per acre and were made at intervals of 7 to 14 daysbeginning when the plants were about 6 inches high. Each test plotreceived only one type of spray and check plots received the DDT spraybut no fungicidal spray. At the end of the season of blight damage,estimates were made The It had the X-ray pattern 2,699,419 Patented Jan.11, 1955 of the amount of combined early and late blight damage; at theend of the growing season the plants showed no damage due tophytotoxicity and the potatoes were ,harvested and weighed. The testswere run on four randomly selected replicate plots for each fungicidetested. The check plot was an integral part of the test, and alsoreplicated four times.

The data obtained from these tests are given in the following Table I.

In the above table, the figures given in the columns headed DiseaseControl are an index obtained by the formula:

(Actual disease control rating for a given treatment) (Average of allthree treatments involved in the test*) *NoTE.-The checks oruntreatedplots were not used in making the average.

Index In the above formula the actual ratings are the sum of theindividual ratings by six trained observers. Each observer gave a plot avalue from O (everything dead of disease) to 20 (perfect), the ratingsbeing for general appearance and reflecting primarily disease controlbut also any depressing effect the treatment had on the vigor of theplants, hastening of maturity, etc. The sum of these six ratings is usedas the disease control figure and therefore would be a perfect record inthis respect. Both early blight and late blight attack were consideredin making these ratings, i. e. the effects of these diseases togetherbut not rated separately.

The figures given in the columns headed Yield are the comparativeweights of potatoes yielded by the test plots and corrected for standexpressed in bushels per acre at the conversion value of 100 bushels peracre equals pounds per plot (1 bushel=60 pounds).

The actual disease control total ratings are given in Table II.

Table II Funglclde Russets Katali dins none (check) 0 0 Bordeaux- 106. 590.0 A 95 81. 5 D 104. 5 93 The data obtained from the tests may also begiven as yield and control indexes as in the following Table III.

*were' obtained in asimilar manner. ease Control lndex-is the average'ofthe Disease Conuntil the plants were thoroughly wet.

In the above table,'the figures given in the column headed Russets wereobtained by the formula:

Actual yield for given treatment Average of all yields on treated plotsThe figures given in the column headed Katahdins The Average Distrol"figures from Table I.

From the foregoing tables it will "be seen that compound D is betterthan compound A in disease control and that better yields are obtainedwhen compound D is used than when either Bordeaux or compound is used.In a series of tests to determine the rungicidal effect vofanotherchromate on early and late blight of tomato plants, potted plants fromabout 6 to 8 inches in height were sprayed until thoroughly wet withhomogeneous aqueous suspensions containing either 0.2% or 0.04%

by weight of a chromate whose analysis indicated the formula4.85CuO-1Cr0z. It had the X-ray pattern shown on line D of the attacheddrawing. The plants were allowed to dry after spraying; and after dryingthe sprayed plants together with unsprayed check plants were inoculatedwith spores of either early blight or late blight. All plants were thentransferred to a greenhouse and from three to live days after suchtransfer the number of blight lesions were counted on the re spectiveplants. Considering the number of lesions on the unsprayed check plantsas 100%, the early blight lesions were only 8% of the-lesions on thecheck plants for the plants sprayed with the 0.2% suspension and only12% for the plants sprayed with the 0.04% suspension. The lesions oflate blights on the plants sprayed with the 0.2% suspension were only 2%and on the plants sprayed with the 0.04% suspension were only 5% of thelate blight lesions on the unsprayed check plants.

In other tests to determine phytotoxicity, a homogeneous aqueoussuspension containing 1% by weight of the aforesaid 4.85CuO-lCrOschromate was sprayed on potted bean and tomato plants about 6 to 8inches high The plants were then transferred to a greenhouse.Observations made about a week after spraying gave the tomato plants anA rating (no injury) and the bean plants an A- rating (very slight andbarely noticeable injury).

The chromates contemplatedherein give good fungi control when applied atrates from 1 to 3 pounds per acre, no phytotoxicity having been shown atthese rates. Economically, the materials are preferably applied at ratesfrom 1.25 to 2.50 pounds per acre. To facilitate the application of thissmall amount of material, it is preferably applied in homogeneouscombination with a carrier or extender.

the type of applicator used. Many agriculturists prefer to spray aqueoussuspensions at rates up to about 150 gallons per acre usually at therate of about 125 gallons per acre. at rates of about 20 gallons peracre or less and from these small gallonages on up to the usual amounts.The inert or extender may be any of the usual dry materials, forinstance powdered talc, infusorial earth, pyrophyllite, celite and thelike, for agriculturists equipped to apply dry fungicides. Dryfungicides are frequently applied at rates of from about 25 to 75 poundsper acre, usually at about 50 pounds'per acre, including extender. Adustcontaining 2% to 6% by weightof active material, applied at 50 poundsper acre 4.5CuO CrOs 5H2O 75.3 gram molesof powdered Cu(OH)2 werestirred into 15.4 gallons of water until a homogeneous slurry wasformed. To the slurry were added 16.67 gram rrioles of CrOs, withstirring, over the space of one-half hour.

-Agitation was continued for an additional three hours after which theprecipitate was filtered off. All mixing Any amount and type of extendermay be used and the selection depends primarily upon Newer spray devicesapply aqueous sprays 21 C.) and tap water was used to prepare theslurry. The precipitate was not washed and after removal from the filterwas dried at 88 C. to constant weight. The dried material was pulverizedto a fineness or less than 0.1% retained on 325 mesh (wet screening).The yield was 16.67 gram moles. When prepared in this way, that is byadding the :CrOs slowly to the Cu(OH)z and-agitating or otherwiseworking the mass while the color changes are occurring and until wellafter there is no further color change, that is agitating until thelight green color is obtainedthroughout the .mass and further working,say for one-half hour or more, does .not affect the color, the producthas the distinctive X-ray pattern shown on line D of the drawing. TheCrOa is preferably used in the solid form as flakesor powder but it maybe used in aqueous solution which, however, is preferably highlyconcentrated. Cupric hydroxide is the reactant preferred over thecorresponding oxide or salts. The oxide'is not as reactive as thehydroxide in this reaction and tends to give a product with a loweramount of combined copp'er'and more free copper oxide while the saltsintroduce contaminants.

f the chromates contemplated herein, those having a greenish cast arepreferred as they are less noticeable onthe plants than Bordeaux andthey are less noticeable than the brown or yellow-brown chromates A andB even though they contain morecopper. Where there is even a remotechance of copper injury, it is preferred to use a chromate whose X-raypattern gives no indication of the presence of copper hydroxide.Thus,'with the chromates contemplated herein,it is'possible to combinethe fungicidal effect of'chromium with'the high fungicidal efiect ofahigh proportion'of copper, .and yet run little or no risk of coppereffect in stunting plants and reducing yields.

\Vhat is claimed is: I

l. A pesticide comprising a basic chromate containing copper and havinga copper to chromium ratio of from greater than 3 to about 6 moles ofcopper to l'mole of hexavalent chromium and having an X-ray patternshowing strong lines at values of 26 of 13.6, 22.3, and 35.5 undercopper Karadiation, the chromate being substantially free from copperhydroxide and such as is prepared by incorporating CrOs into Cu(OH)z andreacting the CrOg with the Cu(OH)2 in the said copper to chromium molarratios, the color of the chromate varying from a yellow brown to a lightgreen to an olive green as the'amount of copper reacted with thechromium increases within said limits.

2. A pesticide comprising a basic chromate containing copper and havinga copper to chromium ratio of from about 4 to'about 5 moles of copper to1 mole of hexavalent chromium and having an X'-ray pattern showingstrong lines at values of 20 of 13.6, 22.3, and 35.5 under copper K06radiation, the chromate being substantially free from copper hydroxideand such as is prepared by incorporating CrOa into Cu(OH)z and reactingthe CrOa with the C11(OH)2 in the said copper to chromium molar ratios,the color of the chromate varying from a yellow brown to a light greento an olive green as the amount of copper reacted with the chromiumincreases within said limits.

3. A pesticide comprising a basic chromate containing copper and havinga copper to chromium ratio'of from greater than 3'to about 6 moles ofcopper to 1 mole of hexavalent chromium and having an X-ray patternshowing strong lines at values of 20 of 13.6, 22.3, and 35.5 undercopper K06 radiation, together with an admixed carrier, the chromatebeing substantially free from copper hydroxide and such as is preparedby incorporating Cl03 into Cu(OH)2 and reacting the CrOs with theCu(OH)2 in the said copper to chromium molar ratios, the color of thechromate varying from a yellow brown to a light green to an olive greenas the amount of copper reacted with the chromium increases within saidlimits.

4. Method of protecting an organic material subject to attack by pestswhich comprises applying to said material a basic chromate containingcopper andhaving a copper to chromium ratio of from greater than 3 toabout 6 moles of copper to 1 mole of hexavalent chromium and having anX-ray "pattern showing strong lines at values of 20 of 13.6, 22.3, and35.5 under copper'Ka radiation, the chromate being substantially freefrom copper hydroxide and such as is prepared by incorporating CrOa intoCu(OH)z and reacting the CrOa with the Cu(OH)2 in the said copper tochromium molar ratios, the color of the chromate varying from a yellowbrown to a light green to an olive green as the amount of copper reactedwith the chromium increases within said limits.

5. Method of protecting plants against attack by pests which comprisesapplying to the plants a basic chromate containing copper and having acopper to chromium ratio of from greater than 3 to about 6 moles ofcopper to 1 mole of hexavalent chromium and having an X-ray patternshowing strong lines at values of 26 of 13.6, 22.3, and 35.5 undercopper KOL radiation, the chromate being substantially free from copperhydroxide and such as is prepared by incorporating CrOs into Cu(OH)2 andreacting the C103 with the Cu(OH)2 in the said copper to chromium molarratios, the color of the chromate varying from a yellow brown to a lightgreen to an olive green as the amount of copper reacted with thechromium increases within said limits.

6. Method of protecting field crop plants against attack by pests whichcomprises applying to the plants a basic chromate containing copper andhaving a copper to chromium. ratio of from greater than 3 to about 6moles of copper to 1 mole of hexavalent chromium and having an X-raypattern showing strong lines at values 25 of 20 of 13.6, 22.3, and 35.5under copper Ka radiation, at a rate of application of from about 1 toabout 3 pounds of the chromate per acre, the chromate beingsubstantially free from copper hydroxide and such as is pre- 6 pared byincorporating C1'O3 into Cu(OH)z and reacting the CrOs with the Cu(OH)zin the said copper to chromium molar ratios, the color of the chromatevarying from a yellow brown to a light green to an olive green as theamount of copper reacted with the chromium increases within said limits.

7. Method of preparing a basic copper-chromate pesticide which comprisesincorporating CrOa into Cu(OH)2 in the molar ratio of from about 3.5 toabout 6 moles of Cu(OH) to 1 mole of CrO3 and working the mass until nocolor change of the mass is obtained upon further working and an X-raypattern of the reacted mass shows strong lines at values of 20 of 13.6,22.3, and 35.5 under copper KOL radiation.

References Cited in the file of this patent UNITED STATES PATENTS1,766,412 Taylor June 24, 1930 2,400,863 Gelfand May 21, 1946 2,438,511McMahon Mar. 30, 1948 2,573,738 Smith et a1. Nov. 6, 1951 2,573,739Whaley Nov. 6, 1951 OTHER REFERENCES Mellor: Comprehensive Treatise onInorganic and Theoretical Chemistry, vol. 11, pages 260 to 262, 1931,Longmans, Green and Co., New York city.

1. A PESTICIDE COMPRISING A BASIC CHROMATE CONTAINING COPPER AND HAVINGA COPPER TO CHROMIUM RATIO OF FROM GREATER THAN 3 TO ABOUT 6 MOLES OFCOPPER TO 1 MOLE OF HEXAVALENT CHROMIUM AND HAVING AN X-RAY PATTERNSHOWING STRONG LINES AT VALUES OF 20 OF 13.6, 22.3, AND 35.5 UNDERCOPPER KA RADIATION, THE CHROMATE BEING SUBSTANTIALLY FREE FROM COPPERHYDROXIDE AND SUCH AS IS PREPARED BY INCORPORATING CRO3 INTO CU(OH)2 ANDREACTING THE CRO3 WITH THE CU(OH)2 IN THE SAID COPPER TO CHROMIUM MOLARRATIOS, THE COLOR OF THE CHROMATE VARYING FROM A YELLOW BROWN TO A LIGHTGREEN TO AN OLIVE GREEN AS THE AMOUNT OF COPPER REACTED WITH THECHROMIUM INCREASES WITHIN SAID LIMITS.
 7. METHOD OF PREPARING A BASICCOPPER-CHROMATE PESTICIDE WHICH COMPRISES INCORPORATING CRO3 INTOCU(OH)2 IN THE MOLAR RATIO OF FROM ABOUT 3.5 TO ABOUT 6 MOLES OF CU(OH)TO 1 MOLE OF CRO3 AND WORKING THE MASS UNTIL NO COLOR CHANGE OF THE MASSIS OBTAINED UPON FURTHER WORKING AND AN X-RAY PATTERN OF THE REACTEDMASS SHOWS STRONG LINES AT VALUES OF 20 OF 13.6, 22.3, AND 35.5 UNDERCOPPER KA RADIATION.